Rate Of Change In Body Mass Index Research Articles

High Variability of Body Mass Index Is Independently Associated With Incident Heart Failure.

Heart failure (HF) is a serious condition with increasing prevalence, high morbidity, and increased mortality. Obesity is an established risk factor for HF. Fluctuation in body mass index (BMI) has shown a higher risk of cardiovascular outcomes. We investigated the association between BMI variability and incident HF. In the UK Biobank, we established a prospective cohort after excluding participants with prevalent HF or cancer at enrollment. A total of 99 368 White participants with ≥3 BMI measures during >2 years preceding enrollment were included, with a median follow-up of 12.5 years. The within-participant variability of BMI was evaluated using standardized SD and coefficient of variation. The association of BMI variability with incident HF was assessed using Fine and Gray's competing risk model, adjusting for confounding factors and participant-specific rate of BMI change. Higher BMI variability measured in both SD and coefficient of variation was significantly associated with higher risk in HF incidence (SD: hazard ratio [HR], 1.05 [95% CI, 1.03-1.08], P<0.0001; coefficient of variation: HR, 1.07 [95% CI, 1.04-1.10], P<0.0001). Longitudinal health records capture BMI fluctuation, which independently predicts HF incidence.

Association Between Body Fat and Body Mass Index from Incomplete Longitudinal Proportion Data: Findings from the Fels Study

Obesity rates continue to exhibit an upward trajectory, particularly in the US, and is the underlying cause of several comorbidities, including but not limited to high blood pressure, high cholesterol, diabetes, heart disease, stroke, and cancers. To monitor obesity, body mass index (BMI) and proportion body fat (PBF) are two commonly used measurements. Although BMI and PBF changes over time in an individual’s lifespan and their relationship may also change dynamically, existing work has mostly remained cross-sectional, or separately modeling BMI and PBF. A combined longitudinal assessment is expected to be more effective in unravelling their complex interplay. To mitigate this, we consider Bayesian cross-domain latent growth curve models within a structural equation modeling framework, which simultaneously handles issues such as individually varying time metrics, proportion data, and potential missing not at random data for joint assessment of the longitudinal changes of BMI and PBF. Through simulation studies, we observe that our proposed models and estimation method yielded parameter estimates with small bias and mean squared error in general, however, a mis-specified missing data mechanism may cause inaccurate and inefficient parameter estimates. Furthermore, we demonstrate application of our method to a motivating longitudinal obesity study, controlling for both time-invariant (such as, sex), and time-varying (such as diastolic and systolic blood pressure, biceps skinfold, bioelectrical impedance, and waist circumference) covariates in separate models. Under time-invariance, we observe that the initial BMI level and the rate of change in BMI influenced PBF. However, in presence of time-varying covariates, only the initial BMI level influenced the initial PBF. The added-on selection model estimation indicated that observations with higher PBF values were less likely to be missing.

Weight Loss and Disease Progression in Amyotrophic Lateral Sclerosis and Primary Lateral Sclerosis (P2-8.009)

<h3>Objective:</h3> We studied the association of changes in body mass index (BMI) with disease progression among amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS) Multicenter Cohort Study of Oxidative Stress (COSMOS) study participants, prospectively followed up to 24 months. <h3>Background:</h3> Weight loss is a poor prognostic factor in ALS. However, less is known about weight change in PLS. <h3>Design/Methods:</h3> Participants had a confirmed diagnosis of ALS or PLS and completed baseline and at least one follow-up visit. The rate of BMI change (ΔBMI) and total revised ALS functional rating scale change (ΔALSFRS-r) were calculated between baseline and the first follow-up. Correlation between ΔBMI and ΔALSFRS-r were assessed using Pearson correlation among ALS and PLS participants separately. The demographics and proportion of participants with swallowing dysfunction at baseline and significant weight loss were compared between ALS and PLS groups using chi-square test. Cox proportional hazard models examined the association between significant weight loss (ΔBMI&lt;−1kg/m2/year) and survival in ALS, adjusted for other prognostic factors. <h3>Results:</h3> 279 ALS and 37 PLS participants were included. Mean age of ALS and PLS were both 60 years and 61% male. At baseline, swallowing dysfunction was more frequent in the PLS (78% vs 48%, p&lt;0.001) while significant weight loss was more frequent in the ALS (53% vs 19%, p&lt;0.001). ΔBMI and ΔALSFRS-r correlated significantly in ALS (r=0.3, p&lt;0.0001) but not in PLS (r= −0.21, p=0.2). Significant weight loss was associated with increased risk of death (hazard ratio 2.08, p&lt;0.0001) in ALS after adjusting for age, disease-duration, bulbar-onset, diagnostic-certainty, riluzole-intake, forced vital capacity, baseline BMI, baseline ALSFRS-r and ΔALSFRS-r. <h3>Conclusions:</h3> In ALS, significant weight loss is a strong independent prognostic factor for survival and rate of BMI change correlates with faster functional decline. In contrast, significant weight loss is infrequent in PLS despite a high prevalence of swallowing dysfunction. <b>Disclosure:</b> Dr. Lee has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Alexion. Dr. Lee has received personal compensation in the range of $0-$499 for serving as a Consultant for Amylyx. Dr. Lee has received personal compensation in the range of $0-$499 for serving on a Scientific Advisory or Data Safety Monitoring board for Regeneron. The institution of Dr. Lee has received research support from Myasthenia Gravis Foundation of America. The institution of Dr. Lee has received research support from CReATe consortium/American Brain Foundation. Dr. Mitsumoto has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Eli Lilly. Pam Factor-Litvak has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for ICF. Pam Factor-Litvak has received personal compensation in the range of $10,000-$49,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Frontiers Publishing. The institution of Pam Factor-Litvak has received research support from NIH. Prof. Nieves has received personal compensation in the range of $5,000-$9,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Bone Health and Osteoporosis Foundation. The institution of Prof. Nieves has received research support from Radius Pharmaceuticals. Prof. Nieves has received personal compensation in the range of $0-$499 for serving as a DSMB member with NIH.

Body Composition Changes Over the Menopausal Transition in Women With and Without Human Immunodeficiency Virus.

Women are at risk for weight gain during the transition to menopause, but few have examined the contribution of menopause to weight gain in women with human immunodeficiency virus (WWH). From 2000 to 2013, participants (621 WWH; 218 without HIV [WWOH]) from the Women's Interagency HIV Study were categorized by menopausal phase using serial measures of anti-Müllerian hormone (AMH). Multivariable linear mixed models examined the association of menopausal phase with body mass index (BMI) and waist circumference (WC) trajectory, stratified by HIV status. In models controlled for chronologic age, the estimated effects (95% confidence interval) of menopausal phase on annual rate of BMI change across early perimenopause, late perimenopause, and menopause, respectively, compared to premenopause were -0.55% (-.80 to -.30), -0.29% (-.61 to .03), and -0.67% (-1.12 to -.20) in WWH, whereas estimated effects were 0.43% (-.01 to .87) and 0.15% (-.42 to .71) across early and late perimenopause, respectively, and -0.40% (-1.24 to .45) across menopause in WWOH. The estimated effects on rate of WC change were negative across early perimenopause (-0.21% [-.44 to .03]) and menopause (-0.12% [-.5 to .26]) and positive across late perimenopause (0.18% [-.10 to .45]) in WWH, and positive across all 3 menopausal phases in WWOH, but these effects were not statistically significant. In WWH, the menopausal transition was associated with BMI and WC trajectories that were mostly in a negative direction and opposite from WWOH after adjusting for age, suggesting that HIV blunts weight gain during the menopausal transition.

Differences in body mass index trajectories of adolescent psychiatric inpatients by sex, age, diagnosis and medication: an exploratory longitudinal, mixed effects analysis.

Adolescents in secure psychiatric care typically report high obesity rates. However, longitudinal research exploring the rate and extent of change is sparse. This study aimed to analyse sex differences in longitudinal body mass index (BMI) change for adolescents receiving treatment in a secure psychiatric hospital. The sample comprised 670 adolescents in secure psychiatric care. BMI trajectories from admission to 50 months of hospitalisation were produced using sex-stratified multilevel models. Systematic difference in mean BMI trajectories according to age at admission (14, 15, 16, or 17 years), medication (Olanzapine or Sodium Valproate), and primary diagnosis (Psychotic, non-Psychotic or Functional/behavioural disorders) were investigated. Together, males and females experienced a mean BMI increase of 2.22 m/kg2 over the 50-month period. For females, BMI increased from 25.69 m/kg2 to 30.31 m/kg2 , and for males, reduced from 25.01 m/kg2 to 23.95 m/kg2 . From 30 to 50 months, a plateau was observed for females and a reduction in BMI observed for males. Psychotic disorders in males (β 3.87; CI 1.1-6.7) were associated with the greatest rate of BMI change. For medication, Olanzapine in females was associated with the greatest rate of change (β1.78; CI -.89-4.47). This is the first longitudinal study exploring longitudinal BMI change for adolescent inpatients. Results highlight that individual differences in adolescent inpatients result in differing levels of risk to weight gain in secure care. Specifically, males with psychotic disorders and females taking Olanzapine present the greatest risk of weight gain. This has implications for the prioritisation of interventions for those most at risk of weight gain.

Effect of elexacaftor-tezacaftor-ivacaftor on body weight and metabolic parameters in adults with cystic fibrosis

BackgroundThough weight gain has been reported in some clinical trials of CFTR modulators, the effect of elexacaftor-tezacaftor-ivacaftor on body weight, body mass index (BMI), blood pressure, lipids and glycemic control in the real-world setting remains incompletely described. MethodsWe performed a single-center, retrospective, observational analysis of the effect of elexacaftor-tezacaftor-ivacaftor on body weight and cardiometabolic parameters in 134 adult CF patients of the Washington University Adult Cystic Fibrosis Center. Body weight, BMI, and blood pressure were extracted from outpatient clinic visits for the year preceding and the period following the initiation of elexacaftor-tezacaftor-ivacaftor. Other metabolic parameters were extracted at baseline and at latest available follow-up. ResultsA mean of 12.2 months of follow-up data was available for analysis. The mean rate of change in BMI was 1.47 kg/m2/yr (95% CI, 1.08 to 1.87) greater after initiation of elexacaftor-tezacaftor-ivacaftor. Significant increases in blood pressure were observed. In those without CFRD, random blood glucose and hemoglobin A1c were decreased after elexacaftor-tezacaftor-ivacaftor initiation. In those with CFRD, elexacaftor-tezacaftor-ivacaftor increased serum total cholesterol, HDL-cholesterol, and LDL-cholesterol. ConclusionsIn this single-center, retrospective, observational study of 134 adults with CF, initiation of elexacaftor-tezacaftor-ivacaftor was associated with increases in BMI at a mean follow up of 12.2 months. Changes in other cardiometabolic risk factors were also observed. Widespread use of elexacaftor-tezacaftor-ivacaftor may be expected to increase the incidence of overnutrition in the CF population.

Transition to Dolutegravir Is Associated With an Increase in the Rate of Body Mass Index Change in a Cohort of Virally Suppressed Adolescents.

BackgroundAntiretroviral therapy (ART) regimens that contain dolutegravir (DTG) have been associated with increases in body mass index (BMI) in adults. However, this relationship has not been well described in adolescents.MethodsIn a retrospective observational cohort of 460 virally suppressed (<200 copies/mL) adolescents living with human immunodeficiency virus at a clinical site in Eswatini, body mass index (BMI) measurements were analyzed between 1 year prior to the transition to DTG and up to 1 year after DTG transition. Random-effects linear spline models were used to describe the rate of change in BMI before and after the transition to DTG.ResultsIn adolescents, BMI increased at a rate of 0.3 kg/m2 per year before DTG transition and increased to a rate of 1.2 kg/m2 per year after DTG transition. Sex of the adolescent modified the relationship between DTG and rate of BMI change: BMI rate of change after DTG transition was increased by 1.1 kg/m2 in females and 0.6 kg/m2 per year in males.ConclusionsTransition to DTG in virally suppressed adolescents (aged 10–19 years) is associated with an increase in the rate of BMI change. Female adolescents may experience a larger change than males. Further investigation is required to elucidate the mechanism that underlies these observations and to assess how DTG impacts BMI in adolescents following longer durations of treatment.

Preoperative Trajectories in Cystic Fibrosis and Their Association with Short and Long Term Survival after Lung Transplantation

Cystic fibrosis (CF) remains a major indication for lung transplantation (LTx). To date, no single objective parameter is predictive of survival after LTx. Worsening of nutritional status and rapidly declining lung function are referral criteria found in the ISHLT guidelines. We aimed to determine whether whether the rate of decline in nutritional status and/or lung function prior to LTx was predictive of survival after LTx. We conducted a retrospective cohort study of CF LTx patients in our institution between 1997 and 2018. BMI (body mass index) and FEV1 (forced expiratory volume in 1 second) values 2 year prior to transplant were collected. For each parameter, patients were divided in two groups according to the rate of change in BMI or FEV1 (linear regression slope). Change in time for these parameters were then assessed using mixed-effect models with knots at every 3 months. During the study period, 198 patients underwent a first double LTx. 9 patients were excluded as they had less than 3 observations for either BMI or FEV1. The remaining patients (n=189) were included in the analysis. The mean BMI slopes were -0,06 and +0,08 kg/m2/month for the two BMI groups, while mean FEV1 slopes were-0,53 and +0,09%/monthin the two FEV1 groups. Linear mixed models for each phenotype are shown in Figure 1. Demographic factors, enteral feeding, post-operative complications and 90-day mortality were similar in all groups. Patients experiencing a preoperative BMI decline have worse 10-year survival after LTx (62 vs 69%), while this effect is not apparent when accounting for FEV1 decline. The FEV1 slope alone does not influence 10-year survival after LTx (65 vs 66%). Our results suggest that the BMI trajectory when used as a marker of nutritional status impacts survival after LTx. The FEV1 trajectory does not appear to significantly impact survival after LTx. A larger study is required to validate these results.

Conversions After Sleeve Gastrectomy for Weight Regain: to Single and Double Anastomosis Duodenal Switch and Gastric Bypass at a Single Institution.

With the increase in popularity of laparoscopic sleeve gastrectomy (LSG), the number of patients experiencing weight regain has increased as well. This study aims to demonstrate the outcomes of LSG conversions to Roux-en-Y gastric bypass (RYGB), double anastomosis duodenal switch (DS), and single anastomosis duodeno-ileal sleeve (SADI-S) due to weight regain. A retrospective chart review was performed on 21 patients who underwent a conversion of LSG due to weight regain between March 1, 2013, and April 30, 2017. A longitudinal analysis was performed for the body mass index (BMI) measures, using multilevel model for change. Of 21 patients, 6 underwent a conversion to RYGB, 9 underwent a conversion to SADI-S, and 6 underwent a conversion to double anastomosis DS. Mean percentage of total weight loss was 16.0% at 6months, 20.1% at 12months, 18.8% at 24months, and 21.8% at 36months after the procedure. The final model suggests that preoperative BMI is the most significant indicator for initial status and the rate of change in BMI. Adjusting for preoperative BMI, type of procedure significantly affected the rate of change in BMI. The rate of decrease was fastest in RYGB patients, adjusting for preoperative BMI. One patient was readmitted 26days after the conversion for pulmonary embolism and intraabdominal hematoma, and no patient required a reoperation within 30days after the conversion. Conversions of LSG to RYGB, double anastomosis DS, and SADI-S are safe and can provide significant additional weight loss.

Ultra-processed food consumption and adiposity trajectories in a Brazilian cohort of adolescents: ELANA study

Background/objectivesIn Brazil, the increase in obesity rates has been accompanied by increased consumption of ultra-processed food (UPF). The objective of this paper was to evaluate body mass index (BMI) and body fat percentage (%BF) trajectories in adolescents over a 3-year follow-up according to the frequency of UPF consumption.Subjects/methodsData of three consecutive years (2010, 2011, and 2012) were obtained from the Adolescent Nutritional Assessment Longitudinal Study (ELANA) that aimed to assess changes in anthropometric indicators of nutritional status, and 1035 adolescents enrolled in the 1st year of high school from six schools (four private and two public) in the metropolitan area of Rio de Janeiro, Brazil were included. At three follow-ups, they had their weights and heights measured. Body composition was measured at the first and second follow-ups. Mixed linear regression models were used to estimate BMI and %BF trajectories based on quartiles of UPF intake, adjusting for type of school, sex, physical activity, and underreporting.ResultsCompared to their counterparts in the 1st quartile, adolescents in the 4th quartile of UPF consumption had a lower daily intake of fruits, cooked vegetables, and raw vegetables and a higher intake of total sugar and physical activity levels (p < 0.001). There was an inverse association between UPF consumption and BMI both at baseline and at follow-up. Values for %BF followed the same trend. Adolescents in the 4th quartile had the greatest level of physical activity and lowest total energy intake.ConclusionThis study confirmed that greater intake of UPF is a marker of an unhealthy diet, but did not support the hypothesis of a high rate of change in BMI associated with greater UPF consumption, even after adjusting for physical activity.

Individual and shared effects of social environment and polygenic risk scores on adolescent body mass index

Juvenile obesity is associated with adverse health outcomes. Understanding genetic and environmental influences on body mass index (BMI) during adolescence could inform interventions. We investigated independent and interactive effects of parenting, socioeconomic status (SES) and polygenic risk on BMI pre-adolescence, and on the rate of change in BMI across adolescence. Genome-wide genotype data, BMI and child perceptions of parental warmth and punitive discipline were available at 11 years old, and parental SES was available from birth on 3,414 unrelated participants. Linear models were used to test the effects of social environment and polygenic risk on pre-adolescent BMI. Change in BMI across adolescence was assessed in a subset (N = 1943). Sex-specific effects were assessed. Higher genetic risk was associated with increased BMI pre-adolescence and across adolescence (p < 0.00417, corrected for multiple tests). Negative parenting was not significantly associated with either phenotype, but lower SES was associated with increased BMI pre-adolescence. No interactions passed correction for multiple testing. Polygenic risk scores from adult GWAS meta-analyses are associated with BMI in juveniles, suggesting a stable genetic component. Pre-adolescent BMI was associated with social environment, but parental style has, at most, a small effect.

Prospective trends in body mass index by main transport mode, 2007–2013

Abstract Background Cohort studies have examined whether change in transport mode is associated with change in bodyweight among commuters. We complement this research by examining trends in body mass index (BMI) for men and women who used the same transport mode between 2007 and 2013, and where transport was used for any activity of daily life. Methods Data are from the HABITAT study, a longitudinal investigation of health among 11,035 persons aged 40–65 residing in 200 neighbourhoods in Brisbane, Australia. Transport mode was measured as private motor vehicle (PMV), public transport, walking, and cycling. Analyses were conducted using random effects models before and after adjustment for time-varying and time-invariant confounders. Interactions between transport mode and time were modelled to assess whether the rate of change in BMI differed by mode. Results Averaged over the four time-points, the BMI of men who consistently walked or cycled was −3.20 kg/m2 (95%CI −4.28, −2.12) and −2.15 kg/m2 (95%CI −3.22, −1.08) lower respectively than PMV users: the corresponding difference for women who walked or cycled was −2.42 kg/m2 (95%CI −3.66, −1.18) and −2.44 kg/m2 (95%CI −5.98, 1.11). For men, there were no BMI differences between PMV and public transport users; among women, those who mainly used public transport had higher BMI (1.06 kg/m2 95%CI 0.51, 1.62) than PMV users. For men, no significant interactions were found between transport mode and time; for women, those who mainly walked for transport experienced a significant decline in BMI compared with PMV users. Conclusion Those who consistently walked or cycled sustained a lower BMI over time relative to those who consistently used a PMV. Transport and land use policies and behavioural interventions that successfully shift mode-share from PMV to active travel might help stem the global increase in obesity related chronic disease.

Neighborhood socioeconomic disadvantage and body mass index among residentially stable mid-older aged adults: Findings from the HABITAT multilevel longitudinal study

Despite a body of evidence on the relationship between neighborhood socioeconomic disadvantage and body mass index (BMI), few studies have examined this relationship over time among ageing populations. This study examined associations between level of neighborhood socioeconomic disadvantage and the rate of change in BMI over time. The sample included 11,035 participants aged between 40 and 65years at baseline from the HABITAT study, residing in 200 neighborhoods in Brisbane, Australia. Data were collected biennially over four waves from 2007 to 2013. Self-reported height and weight were used to calculate BMI, while neighborhood disadvantage was measured using a census-based composite index. All models were adjusted for age, education, occupation, and household income. Analyses were conducted using multilevel linear regression models. BMI increased over time at a rate of 0.08kg/m2 (95% CI 0.02, 0.13) and 0.17kg/m2 (95% CI 0.11, 0.29) per wave for men and women respectively. Both men and women residing in the most disadvantaged neighborhoods had a higher average BMI than their counterparts living in the least disadvantaged neighborhoods. There were no evident differences in the rate of BMI change over time by level of neighborhood disadvantage. The findings suggest that by mid-older age, the influence of neighborhood socioeconomic conditions over time on BMI may have already played out. Future research should endeavor to identify the genesis of neighborhood socioeconomic inequalities in BMI, the determinants of these inequalities, and then suitable approaches to intervening.

Prospective associations between diet quality and body mass index in disadvantaged women: the Resilience for Eating and Activity Despite Inequality (READI) study.

Dietary patterns that align with recommended guidelines appear to minimize long-term weight gain in the general population. However, prospective associations between diet quality and weight change in disadvantaged adults have not been examined. This study examined associations between concurrent change in diet quality and body mass index (BMI) over 5 years among women living in socioeconomically disadvantaged neighbourhoods. Dietary intake and BMI were self-reported among 1242 women living in disadvantaged neighbourhoods in Victoria, Australia, at three time points from 2007/08 to 2012/13. Diet quality was evaluated using the Australian Dietary Guideline Index (DGI). Associations between concurrent change in diet quality and BMI were assessed over the three time points using fixed effects and mixed models. Models were adjusted for age, smoking, menopausal status, education, marital status, number of births, urban/rural location and physical activity. Average BMI increased by 0.14 kg/m2 per year increase in age in the fixed effects model, and by 0.13 kg/m2 in the mixed model (P < 0.0001). BMI decreased by 0.014 kg/m2 for a woman of average age with each unit increase in DGI score in the fixed effects model (p < 0.0001), and by 0.012 kg/m2 in the mixed model (P = 0.001). The rate of change in BMI with age was greater for those with a lower DGI score than for those with a higher score (P < 0.10). Positive change in diet quality was associated with reduced BMI gain among disadvantaged women. Supporting disadvantaged women to adhere to population-level dietary recommendations may assist them with long-term weight management.

Will I get fat? 22-year weight trajectories of individuals with eating disorders.

For some, fat phobia or fear of uncontrollable weight gain is diagnostic of eating disorders, often inhibiting treatment engagement and predicting symptom relapse. Prior research has reported weight changes at infrequent or long intervals, but rate, shape, and magnitude of long-term changes remain unknown. Our study examined 22-year longitudinal trajectories of body mass index (BMI) in women with anorexia nervosa (AN) and bulimia nervosa (BN). Participants were followed over 10 years (N = 225) and at 22-year follow-up (N = 175). Using latent growth curves, we examined: (1) shape and rate of intra-individual BMI change over 10 years; (2) predictors of BMI change over 10 years, (3) 22-year BMI outcomes; and (4) BMI changes over 10 years as predictors of 22-year BMI. The best-fitting model captured overall intra-individual rates of BMI change in three intervals, showing moderate rate of BMI increase from intake to year 2, modest increase from year 2 to 5, and plateau from year 5 to 10. At 22 years, 14% were underweight, 69% were normal weight, and only 17% were overweight or obese. Greater increases from intake to year 2 predicted higher BMI at 22 years (β = 0.43, p < 0.01) and were predicted by intake diagnosis of AN-restricting (β = 0.31, p < 0.01) or AN-binge eating/purging (β = 0.29, p < 0.01). BMI increased most rapidly during earlier years of the study for those with lower weight at study intake (i. e., AN) and plateaued over time, settling in the normal range for most. Psychoeducation about expected BMI trajectory may challenge patients' long-term fat phobic predictions.

Obesity trends and risk factors in the South African adult population.

BackgroundObesity prevalence is increasing globally and contributes substantially to the burgeoning burden of non-communicable diseases. South Africa is particularly affected by this increasing trend and cross-sectional evidence suggests socioeconomic and behavioural variables as possible drivers. However, no large scale longitudinal study has attempted the direct identification of risk factors for progression towards obesity.MethodsThis study analysed data on 10,100 South African adults (18 years and over) randomly selected in 2008 and successfully recontacted in 2010 and 2012. Latent Growth Modelling was used to estimate the average rate of change in body mass index (BMI) during the study period, and to identify baseline characteristics associated with different trajectories.ResultsThe overall rate of change in BMI during the study period was +1.57 kg/m2 per decade (95 % CI: 0.93 −2.22), and it was higher among women (+ 1.82 kg/m2 per decade, 95 % CI: 1.06 −2.58) than among men (+ 1.03 kg/m2 per decade; 95 % CI: 0.14 −1.93).Female gender, younger age, larger waist circumference, white population group and higher household income per capita were baseline characteristics associated with higher rates of change.The association between tobacco use and obesity was complex. Smoking was associated with greater waist circumference at baseline but lower rates of increase in BMI during the study period. Quitting smoking was an independent predictor of BMI increase among subjects with normal weight at baseline.Among subjects with baseline BMI lower than 25 kg/m2, rates of changes were higher in rural than urban areas, and inversely related to the frequency of physical exercise.ConclusionsA strong positive trend in BMI remains in South Africa and obesity prevalence is likely to increase. Trends are not homogeneous, and high risk groups (subjects with high socioeconomic status, rural dwellers, young women) and modifiable risk factors (physical inactivity) can be targeted. Subjects quitting smoking should receive additional weight-loss support in order that the numerous health benefits of cessation are not reduced by increasing BMI. Centrally obese subjects should be targeted in campaigns.Electronic supplementary materialThe online version of this article (doi:10.1186/s40608-015-0072-2) contains supplementary material, which is available to authorized users.

Variability and rapid increase in body mass index during childhood are associated with adult obesity.

Body mass index (BMI) in childhood predicts obesity in adults, but it is unknown whether rapid increase and variability in BMI during childhood are independent predictors of adult obesity. The study cohort consisted of 1622 Bogalusa Heart Study participants (aged 20 to 51 years at follow-up) who had been screened at least four times during childhood (aged 4-19 years). BMI rate of change during childhood for each individual was assessed by mixed models; BMI residual standard deviation (RSD) during childhoodwas used as a measure of variability. The average follow-up period was 20.9 years. One standard deviation increase in rate of change in BMI during childhood was associated with 1.39 [95% confidence interval (CI): 1.17-1.61] kg/m(2) increase in adult BMI and 2.98 (95% CI: 2.42-3.56) cm increase in adult waist circumference, independently of childhood mean BMI. Similarly, one standard deviation increase in RSD in BMI during childhood was associated with 0.46 (95% CI: 0.23-0.69) kg/m(2) increase in adult BMI and 1.42 (95% CI: 0.82-2.02) cm increase in adult waist circumference. Odds ratio for adult obesity progressively increased from the lowest to the highest quartile of BMI rate of change or RSD during childhood (P for trend < 0.05 for both). Rapid increase and greater variability in BMI during childhood appear to be independent risk factors for adult obesity. Our findings have implications for understanding body weight regulation and obesity development from childhood to adulthood.

A genome-wide association study of body mass index across early life and childhood.

Background: Several studies have investigated the effect of known adult body mass index (BMI) associated single nucleotide polymorphisms (SNPs) on BMI in childhood. There has been no genome-wide association study (GWAS) of BMI trajectories over childhood.Methods: We conducted a GWAS meta-analysis of BMI trajectories from 1 to 17 years of age in 9377 children (77 967 measurements) from the Avon Longitudinal Study of Parents and Children (ALSPAC) and the Western Australian Pregnancy Cohort (Raine) Study. Genome-wide significant loci were examined in a further 3918 individuals (48 530 measurements) from Northern Finland. Linear mixed effects models with smoothing splines were used in each cohort for longitudinal modelling of BMI.Results: A novel SNP, downstream from the FAM120AOS gene on chromosome 9, was detected in the meta-analysis of ALSPAC and Raine. This association was driven by a difference in BMI at 8 years (T allele of rs944990 increased BMI; PSNP = 1.52 × 10−8), with a modest association with change in BMI over time (PWald(Change) = 0.006). Three known adult BMI-associated loci (FTO, MC4R and ADCY3) and one childhood obesity locus (OLFM4) reached genome-wide significance (PWald < 1.13 × 10−8) with BMI at 8 years and/or change over time.Conclusions: This GWAS of BMI trajectories over childhood identified a novel locus that warrants further investigation. We also observed genome-wide significance with previously established obesity loci, making the novel observation that these loci affected both the level and the rate of change in BMI. We have demonstrated that the use of repeated measures data can increase power to allow detection of genetic loci with smaller sample sizes.

Modification of genetic influences on adiposity between 36 and 63 years of age by physical activity and smoking in the 1946 British Birth Cohort Study.

Background:Previous studies reporting on the interaction between physical activity and genetic susceptibility on obesity have been cross-sectional and have not considered the potential influences of other lifestyle behaviours. The aim of this study was to examine modification of genetic influences on changes across age in adiposity during mid-adulthood by physical activity and smoking.Methods:The sample comprised 2444 participants who were genotyped for 11 obesity variants and had body mass index (BMI), waist circumference-to-height ratio (WHtR), physical activity and smoking measures at 36, 43, 53 and 60–64 years of age. A genetic risk score (GRS) comprising the sum of risk alleles was computed. Structural equation models investigated modification of the longitudinal GRS associations by physical activity (active versus inactive) and smoking (non-smoker versus smoker), using a latent linear spline to summarise BMI or WHtR (multiplied by 100) at the age of 36 years and their subsequent rates of change over age.Results:Physical activity at the age of 36 years attenuated the GRS associations with BMI and WHtR at the same age (P-interaction 0.009 and 0.004, respectively). Further, physical activity at the age of 53 years attenuated the GRS association with rate of change in BMI between 53 and 63 years of age (by 0.012 kg m−2 per year (95% confidence interval (CI): 0.001, 0.024), P-interaction 0.004). Conversely, smoking at the age of 43 years showed a trend towards augmenting the GRS association with rate of change in WHtR between 43 and 63 years of age (by 0.012 (95% CI: 0.001, 0.026), P-interaction 0.07). Estimated GRS effect sizes were lowest at all ages in the healthiest group (e.g., active non-smokers).Conclusions:Healthy lifestyle behaviours appeared to attenuate the genetic influence on changes across age in BMI and central adiposity during mid-adulthood. An active lifestyle and not smoking may have additive effects on reducing the genetic susceptibility to obesity in adults.

Body Mass Index and Risk of Incident Hypertension Over the Life Course

Background— The obesity-hypertension link over the life course has not been well characterized, although the prevalence of obesity and hypertension is increasing in the United States. Methods and Results— We studied the association of body mass index (BMI) in young adulthood, into middle age, and through late life with risk of developing hypertension in 1132 white men of The Johns Hopkins Precursors Study, a prospective cohort study. Over a median follow-up period of 46 years, 508 men developed hypertension. Obesity (BMI ≥30 kg/m 2 ) in young adulthood was strongly associated with incident hypertension (hazard ratio, 4.17; 95% confidence interval, 2.34–7.42). Overweight (BMI 25 to &lt;30 kg/m 2 ) also signaled increased risk (hazard ratio, 1.58; 95% confidence interval, 1.28–1.96). Men of normal weight at age 25 years who became overweight or obese at age 45 years were at increased risk compared with men of normal weight at both times (hazard ratio, 1.57; 95% confidence interval, 1.20–2.07), but not men who were overweight or obese at age 25 years who returned to normal weight at age 45 years (hazard ratio, 0.91; 95% confidence interval, 0.43–1.92). After adjustment for time-dependent number of cigarettes smoked, cups of coffee taken, alcohol intake, physical activity, parental premature hypertension, and baseline BMI, the rate of change in BMI over the life course increased the risk of incident hypertension in a dose-response fashion, with the highest risk among men with the greatest increase in BMI (hazard ratio, 2.52; 95% confidence interval, 1.82–3.49). Conclusions— Our findings underscore the importance of higher weight and weight gain in increasing the risk of hypertension from young adulthood through middle age and into late life.